A power storage device described in Patent Document 1 includes a first internal electrode extended to a first end surface, a second internal electrode extended to a second end surface, and a separator disposed between the first internal electrode and the second internal electrode. A first external electrode electrically connected to the first internal electrode is disposed on the first end surface. A second external electrode electrically connected to the second internal electrode is disposed on the second end surface. An electrical double layer capacitor described in Patent Document 1 has an advantage that it can be mounted on a mounting substrate.
Patent Document 1: International Publication No. 2014/083919